More than 36 million Americans are on alert for severe weather in the Midwest, with thunderstorms, large hail and a tornado outbreak possible on Monday.

The FOX Forecast Center is monitoring the development of a likely tornado outbreak across portions of the Upper Midwest on Monday, with millions of people in cities like Minneapolis on alert for severe weather.

The severe weather threat extends beyond the Upper Midwest, affecting more than 45 million people from Texas to the U.S.-Canada border.

Millions in the Upper Midwest face the possibility of a severe thunderstorm outbreak Monday—the start of several days of extreme weather threats across the country this week.

Officials in the Upper Midwest warned of possible power outages and closed some schools early as the storms loomed.